In the formation of color paper it is known that the base paper has applied thereto a layer of polymer, typically polyethylene. This layer serves to provide waterproofing to the paper, as well as providing a smooth surface on which the photosensitive layers are formed. The formation of a suitably smooth surface is difficult requiring great care and expense to ensure proper laydown and cooling of the polyethylene layers. The formation of a suitably smooth surface would also improve image quality as the display material would have more apparent blackness as the reflective properties of the improved base are more specular than the prior materials. As the whites are whiter and the blacks are blacker, there is more range in between and, therefore, contrast is enhanced. It would be desirable if a more reliable and smoother surface could be formed at less expense.
Prior art photographic reflective photographic papers are coated with light sensitive silver halide imaging layers on one side of the paper and thus images only appear on one side of the photographic paper. Typically, the side opposite the imaging layers contains the manufacture brand name and is coated with an antistatic coating. Prior art photographic paper is typically conveyed on the backside during manufacture of the paper and in photographic processing as contact with the numerous rollers and platens in manufacturing and photographic image processing would scratch the imaging layers reducing the quality of the image. Further, photographic printing equipment is currently configured to print only one side of the photographic paper.
Prior art two-sided photographs or reflective photographs with images on both sides are accomplished by printing two separate photographs and adhesively adhering the two photographs after imaging processing. While this process does yield a two-sided photograph, it is expensive and time consuming as thickness of the two-sided photograph is excessive. The thick, two-sided image is difficult to handle, expensive to mail and does not easily fit into photographic albums and frames designed for a single thickness of paper.
It has been proposed in U.S. Pat. No. 5,866,282 Bourdelais et al to utilize a composite support material with laminated biaxially oriented polyolefin sheets as a photographic imaging material. In U.S. Pat. No. 5,866,282, biaxially oriented polyolefin sheets are extrusion laminated to cellulose paper to create a support for silver halide imaging layers. The biaxially oriented sheets described in U.S. Pat. No. 5,866,282 have a microvoided layer in combination with coextruded layers that contain white pigments. The composite imaging support structure described in U.S. Pat. No. 5,866,282 has been found to be more durable, sharper and brighter than prior art photographic paper imaging supports that use cast melt extruded polyethylene layers coated on cellulose paper.
Typically, photographic reflective imaging layers are coated on a polyethylene coated cellulose paper. While polyethylene coated cellulose paper does provide an acceptable support for the imaging layers, there is a need for alternate support materials such as polyester or fabric. The problem with alternate, non paper supports is the lack of robustness in photographic processing equipment to mechanical property changes in supports. The photographic processing equipment will not run photographic materials that have significantly different mechanical properties than prior art photographic materials. It would be desirable if a reflective photographic image could be efficiently formed on alternate supports.
The continuing thrust towards digital printing of photographic color papers has created the need for a consumer color paper that can work in both a negative working optical and digital exposure equipment. In order for a color paper to correctly print, utilizing a color negative curve shape of the paper is critical. In a digital environment (direct writing) to a photographic paper, the curve shape to a degree can be electomodulated and thus have a greater degree of freedom than the color negative working system. Ideally, a color paper that could substantially maintain tone scale from conventional optical negative working exposure times to sub microsecond digital direct writing exposure times would be preferred. This would enable a photofinishing area to maintain one paper for both digital and optical exposure thereby reducing the need for expensive inventory.